since (the) year one

: from a definite past time until now

: before the present time : ago

: after a time in the past : subsequently

: at a time in the past after or later than : from the time in the past when

: when

: in view of the fact that : because

: in the period after a specified time in the past : from a specified time in the past

: the period of about 365¹/₄ solar days required for one revolution of the earth around the sun

: the time required for the apparent sun to return to an arbitrary fixed or moving reference point in the sky

: the time in which a planet completes a revolution about the sun